I agree with most of the points here about leaving FIFA but I'd be interested to know how much of the views we've heard are Eurocentric. I'm not sure the rest of the world stands with us on this. For most, FIFA has done wonders for their national teams since 1978.
It's worth noting, that the before then, the last English president of FIFA (Sir Stanley Raus) backed South African apartheid and was prepared to split the CAF federation just to allow them to play (they were banned by CAF). He had to back down when the whole of Africa threatened to leave FIFA and in the next election, the presidency left Europe for the first time. During the Raus years, there were 16 teams at a world cup -13 of which were European or South American with just 3 going to the entire rest of the world.
I think reform is necessary as is transparency. FIFA need a presidency which rotates around federations every 4 years, and a strict set of rules which must be met before a country is even considered to host a world cup. Reform would be better than quitting in my opinion. The World Cup is much better for having more inclusivity.